Illuminator for biological test plates

ABSTRACT

A laboratory lamp is provided for supplying a constant source of daylight-bright, soft, evenly diffused light for the examination of test plates which are translucent or transparent. A generally cylindrical housing has a recess in the center of its top wall for holding a plate to be examined. Near the bottom of the housing is a white light source providing light emitted evenly around a circumference substantially concentric with the cylindrical housing. A light baffle is supported in the housing between the light source and the plate opening preventing direct light beam transmission from the light source to the plate opening but leaving an annular opening substantially continuously around the baffle between its periphery and the interior of the cylindrical housing. The interior surface of the housing, and preferably the underside of said baffle, provide softly diffusing light deflectors. The light intensity may be varied by adjusting the baffle up or down within the housing.

United States Patent [is] 3,643,078 Lewis Feb. 15, 1972 [54] ILLUMINATOR FOR BIOLOGICAL FOREIGN PATENTS OR APPLICATIONS TEST PLATES 348,061 4/1931 Great Britain ..240/2 AT 72 Inventor: Andrew Le 14718 On R d, 1 Shaker l f g 44120 away 0a Primary Examiner-Charles A. Ruehl Attorney--Baldw1n, Egan, Walling & Fetzer [22] Filed: June 29, 1970 [21 Appl. No.: 50,550 [571 ABSTRACT A laboratory lamp is provided for supplying a constant source 52 us. Cl. ..240/2 R, 240/4603, 24051.12 of daylight-bright, soft, evenly diffused light for the examine- [51] lnt.Cl. ..F2lv 33/00 tion of lest Plates which are translucent p A [58] Field of Search ..240/2 R, 2 MA, 2 AT, 41.], generally y ri ing has a re in the enter of its 240/4603, 46.05, 46.19, 46.21, 46.29, 46.47, 20, top wall for holding a plate to be examined. Near the bottom 5 1.12; 40/ 106.1 of the housing is a white light source providing light emitted evenly around a circumference substantially concentric with RQIBNMQS C t the cylindrical housing. A light baffle is supported in the housing between the light source and the plate opening preventing UNITED STATES PATENTS direct light beam transmission from the light source to the 2,516,270 7/1950 Swain ..240/46.03 X plate opening but leaving an annular opening substantially 2,691,918 10/1954 Robins et al.. ....240/2 MA X continuously around the baffle between its periphery and the 3,112,337 63 Broil et a1 240/2 AT interior of the cylindrical housing. The interior surface of the ,813 8/1965 Weinstein 2 X housing, and preferably the underside of said baffle, provide 3,513,585 5/1970 Ross ..240/2 X ftl diff i light deflecwm The light intensity may be varied by adjusting the baffle up or down within the housing.

10 Claims, 2 Drawing Figures I l I 31 u L 24 28 IO l 2 I a W 1"? ill (l CL 16 l7 I 0..

is is PATENTEDFEB 1 s 1972 INVENTOR ILLUMINATOR FOR BIOLOGICAL TEST PLATES A problem is encountered in providing the proper illumination for the examination of biological test plates showing reactions which form precipitations, agglutinations, flocculations, bacterial colony growth, etc. This includes gel diffusion, immunoelectrophoresis and the like, as well as the examination of photographic plates. The illuminator disclosed herein incorporates a fluorescent light bulb of generally circular shape located concentrically in the bottom of a cylindrical housing, the light from which is reflected from the walls of the housing by means of a baffle imperforate in the center of the housing but allowing even distribution of the light from the fluorescent bulb passing peripherally around the baffle and reflected from the cylindrical housing toward the plate to be examined which is held in a recess at the central portion of the top wall of the housing. The interior surface of the housing and, preferably, the underside of the baffle are rendered softly diffusing such as by the use of an aluminum surface or a dull white paint finish. Other objects and advantages of this invention are set forth in the accompanying drawings and specification and the essential features thereof will be set forth in the appended claims.

In the drawings, v

FIG. 1 shows a view of the illuminator of this invention partly in side elevation but largely in central sectional view taken along the line 1-l of FIG. 2; while FIG. 2 is a sectional view of the same taken along the line 2-2 of FIG. 1. The drawings show a generally cylindrical housing having a top wall 11 and a bottom wall 12. Preferably, the bottom wall is held in position by a clamping ring 13 which is of generally half toric formation opening radially inwardly as seen in FIG. 1 and snugly embracing an upwardly opening arcuate flange 12a extending around the periphery of the bottom wall 12 and in turn embracing a bead 10a provided at the lower end of the cylindrical housing 10. As seen in FIG. 2, the clamping ring terminates in two generally parallel radially outwardly extending ears 13a held together by a screw 14 having a head at one end and a knurled nut at the opposite end.

For supporting the housing on a desk or counter top, the housing is mounted upon a base 15, preferably weighted, and carrying on its upper surface toward one side thereof, a pivot block 16 rigidly secured to the base. A generally inverted U- shape bracket 17 is secured to the bottom 12 by screws 18 and is provided with downwardly turned ears 170 at its opposite ends adapted to lie close to the endsof the block 16. A hinge pivot is provided by a knob 19 having a shaft 19a which is threaded into one end of block 16 in coaxial alignment with a pin 20 which is threaded into the opposite end of the block 16. Preferably, the shaft 190 has a shoulder 19b which rests firmly against the adjacent ear 17a when the knob 19 is firmly seated in the block 16. This provides a hinge connection which permits the housing 10 to be tilted toward the viewer, as seen in the drawings, at an angle of about 45 to the vertical. In the assembled position of the parts as shown in the drawings, a short pin 21 extends downward rigidly from the bottom wall 12 and rests upon the top surface of the base to hold the bottom wall horizontal.

A planar light baffle 22 is supported in the housing 10 in approximately horizontal position between the fluorescent tube 23 in the lower part of the housing and the test plate support 24 in the upper part of the housing. The light source 23 is of a character to provide a white light which is emitted evenly around a circumference substantially concentric in the cylindricalhousing 10. Such a suitable source is a substantially circular fluorescent light bulb. A plurality of clamps 25 supported on the lower wall 12 hold the fluorescent bulb in proper position. Electrical power for the light source is supplied through line 26 which connects through suitable ballast and other suitable controls for the light bulb in the base 19, and then electrical wires (not shown) extend from the base 15 through the wall 12 to the light bulb 23 at a point adjacent to the pivot connection 16, 17. The control switch for the light bulb is indicated at 27.

The baffle 22, as best seen in FIG. 2, is generally circular in shape and substantially concentric with the inner wall of the cylindrical housing 10 so as to leave an annular open space of radial dimension A as indicated in FIG. 2 around substantially the entire periphery of the baffle. The central portion of the baffle is imperforate and prevents direct light traveling from the circular light bulb 23 directly to the plate-receiving recess 24. The baffle is preferably mounted for vertical adjustment as best seen in FIG. 1. A vertically extending threaded rod 28 is held at its lower end for free rotation in a bracket29 which is secured to the housing 10. At its upper end, the rod is provided with a manipulating knob 30 and is held in position by a shoulder member 31' so that the threaded rod is freely rotatable by manipulation of the knob 30. The threaded rod has a threaded connection with a stud 31 which is rigidly connected, as by welding, with an ear 22a on the baffle 22. The baffle is held concentric in the housing by means of this ear 22a and three radially projecting points 22b which assure that the baffle remains centered and free from'any substantial tilting from the horizontal position within the housing.

The top wall 11 of the housing 10 is provided centrally with a circular indented recess 11a through which there is an opening 11b for impingement of light rays against whatever plate is in the recess. Preferably, the recess is of a diameter to accommodate l00 mm. Petri dishes, with a set of adapters which will fit in the recess lla and accommodate 35 mm. plates and immunoelectrophoresis slides as well as a transparent millimeter scale for measurement of ring precipitin lines. Preferably also, a short arcuate eyeshield 32 is fixed to the top wall 11 at one side of the central opening to aid the operator in viewing the plates being examined.

The use of this invention will now be clearly understood. With the base 15 resting upon a table or counter, the material to be examined is placed in the recess 1 la either with or without an adapter depending upon the diameter of the dish or plate to be examined. The switch 27 is placed in the lampenergizing position and the operator views the illuminated plate over the eyeshield 32. The light intensity may be varied by adjusting the baffle 22 up ordown by rotating the adjustment knob30 in the appropriate direction which causes the threaded stud 31 to travel up or down the rod 28, thus adjusting the height of the baffle 22 relative to the lamp bulb 23.

The illuminator described herein provides a constant source of unusually even, daylight-bright, soft diffused light used by immunologists to interpret precipitin lines formed in gel diffusion plates or immunoelectrophoresis. Bacteriologists find it useful to read various forms of hemolysis, colonial characteristics, or colony counts. In addition, there may be provided a bacteria colony count grid and/or a transparent adapter designed for quantification of reactions, such as those referred to above. Such a transparent adapter may be equipped with a millimeter scale having two lines at intersecting at the center which is the zero point on scales which increase numerically outwardly in each of four directions.

There is illustrated in FIG. 1 dot-dash lines showing how light beams may travel from the fluorescent light bulb 23 to the inside walls of the cylindrical housing 10 outside of the imperforate baffle 22 to be reflected back to the opening 11b where the plate is being examined. Other beams may travel as shown in dot-dot-dash lines in FIG. 1 anywhere past the circular periphery of the baffle 22. Preferably, the baffle 22 has a dull black coating on its upper surface and a dull white diffus ing coating on its undersurface.

What is claimed is:

1. An illuminator for providing a constant source of daylight-bright, soft, evenly diffused light for the examination of test plates which are at least translucent; comprising a generally cylindrical housing having top and bottom walls; there being a through opening centrally of said top wall for holding a plate to be examined; a white light source having a support in the lower portion of said housing and providing light emitted evenly around a circumference substantially concentric in said cylindrical housing; a planar light baffle in said housing between said light source and said plate opening; said baffle being imperforate and preventing direct light beam transmission from said light source to said plate opening; there being an annular opening substantially continuously around said baffle between its periphery and said cylindrical housing; said annular opening being substantially of constant radial width at substantially all points; means mounting said baffle in said housing; and the interior surfaces of said housing being softly diffusing light reflectors.

2. An illuminator as defined in claim 1, wherein said bafflemounting means is disposed in said housing and comprises opening and centering said baffle in said housing.

5. An illuminator as defined in claim 4, wherein the upper surface of said baffle has a dull black coating and the lower surface thereof has a light-diffusing coating.

6. An illuminator as defined in claim I, wherein said light source is a substantially circular fluorescent tube emitting white light.

7. An illuminator as defined in claim 6, wherein means is provided for removably attaching said bottom wall to said housing, and said light source support comprises clips mounted on said bottom wall which support said fluorescent tube.

8. An illuminator as defined in claim 1, including a base for supporting said housing on a flat surface and a pivotal mounting on said base pivotally connected to said housing near one side of said bottom wall.

9. An illuminator as defined in claim 1, wherein said reflecting surfaces of said housing are aluminum.

10. An illuminator as defined in claim 1, wherein said reflecting surfaces of said housing are provided by a diffusing white coating. 

1. An illuminator for providing a constant source of daylightbright, soft, evenly diffused light for the examination of test plates which are at least translucent; comprising a generally cylindrical housing having top and bottom walls; there being a through opening centrally of said top wall for holding a plate to be examined; a white light source having a support in the lower portion of said housing and providing light emitted evenly around a circumference substantially concentric in said cylindrical housing; a planar light baffle in said housing between said light source and said plate opening; said baffle being imperforate and preventing direct light beam transmission from said light source to said plate opening; there being an annular opening substantially continuously around said baffle between its periphery and said cylindrical housing; said annular opening being substantially of constant radial width at substantially all points; means mounting said baffle in said housing; and the interior surfaces of said housing being softly diffusing light reflectors.
 2. An illuminator as defined in claim 1, wherein said baffle-mounting means is disposed in said housing and comprises means for holding said baffle in horizontal position and for adjusting said baffle vertically.
 3. An illuminator as defined in claim 2, wherein said baffle holding and adjusting means comprises a threaded bushing rigidly connected with said baffle, a vertically extending threaded rod in said bushing, and means mounting said rod in said housing for rotation about its axis.
 4. An illuminator as defined in claim 3, including a small number of pointed projections extending radially outward from said baffle at spaced points about its perimeter, said projections extending across a major portion of said annular opening and centering said baffle in said housing.
 5. An illuminator as defined in claim 4, wherein the upper surface of said baffle has a dull black coating and the lower surface thereof has a light-diffusing coating.
 6. An illuminator as defined in claim 1, wherein said light source is a substantially circUlar fluorescent tube emitting white light.
 7. An illuminator as defined in claim 6, wherein means is provided for removably attaching said bottom wall to said housing, and said light source support comprises clips mounted on said bottom wall which support said fluorescent tube.
 8. An illuminator as defined in claim 1, including a base for supporting said housing on a flat surface and a pivotal mounting on said base pivotally connected to said housing near one side of said bottom wall.
 9. An illuminator as defined in claim 1, wherein said reflecting surfaces of said housing are aluminum.
 10. An illuminator as defined in claim 1, wherein said reflecting surfaces of said housing are provided by a diffusing white coating. 